The present invention relates generally to devices, systems and methods for delivery of a fluid, and, particularly, for infusion or injection of a fluid into a patient.
A number of injector-actuated syringes and powered injectors for use in medical procedures such as angiography, computed tomography (CT), ultrasound and NMR/MRI have been developed. U.S. Pat. No. 4,006,736, for example, discloses an injector and syringe for injecting fluid into the vascular system of a human being or an animal. Typically, such injectors comprise drive members such as pistons that connect to a syringe plunger. For example, U.S. Pat. No. 4,677,980, the disclosure of which is incorporated herein by reference, discloses an angiographic injector and syringe wherein the drive member of the injector can be connected to, or disconnected from, the syringe plunger at any point along the travel path of the plunger via a releasable mechanism. A front-loading syringe and injector system is also disclosed in U.S. Pat. No. 5,383,858, the disclosure of which is incorporated herein by reference.
Although significant advances have been made in the design and operation of powered injectors, a number of problems persist which can limit their use. For example, each year in the United States several million MRI procedures are performed. However, powered injectors are used in only a relatively small percentage of such procedures. In MRI procedures in which there is no need to accurately control the timing of contrast injection or the flow rate of injection, powered injectors are almost never used. In that regard, MRI procedures are relatively expensive and patient throughput is a primary concern. It is perceived that use of powered injectors in such procedures will require additional time, while providing little benefit. Thus, in contrast-enhanced procedure in which timing and flow rate control are not important, contrast is currently injected manually. Typically, the patient is placed in the MRI bore and a baseline scan is performed. The patient is then removed from the bore of the imaging device and the contrast is injected. The patient is then once again placed in the bore and the contrast-enhanced imaging is performed.
A number of problems often arise with the manual injection of contrast in an MRI procedure. For example, after injection it is often difficult to reposition the patient in the same position in which the baseline measurement was made. Even if repositioning can be achieved with success, removal of the patient from the bore to manually inject contrast and subsequent repositioning require a substantial amount of time. Moreover, in some instances, particularly with claustrophobic patients, the patient refuses to reenter the bore. Furthermore, it is sometimes difficult with some patients to properly inject the contrast manually. In such cases, it may become necessary to call for the services of an IV specialist team, greatly increasing the amount of time required for the scan.
Even in imaging procedures other than MRI procedures (such as CT, angiography and ultrasound), there may be reluctance to use powered injectors in certain procedures because of perceived or actual burdens with such use.
For the above reasons and others, it is desirable to develop improved devices, systems and methods for the injection of fluids into patients.